1// Temporary buffer implementation -*- C++ -*-
2
3// Copyright (C) 2001, 2002, 2004, 2005 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 2, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// You should have received a copy of the GNU General Public License along
17// with this library; see the file COPYING.  If not, write to the Free
18// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
19// USA.
20
21// As a special exception, you may use this file as part of a free software
22// library without restriction.  Specifically, if other files instantiate
23// templates or use macros or inline functions from this file, or you compile
24// this file and link it with other files to produce an executable, this
25// file does not by itself cause the resulting executable to be covered by
26// the GNU General Public License.  This exception does not however
27// invalidate any other reasons why the executable file might be covered by
28// the GNU General Public License.
29
30/*
31 *
32 * Copyright (c) 1994
33 * Hewlett-Packard Company
34 *
35 * Permission to use, copy, modify, distribute and sell this software
36 * and its documentation for any purpose is hereby granted without fee,
37 * provided that the above copyright notice appear in all copies and
38 * that both that copyright notice and this permission notice appear
39 * in supporting documentation.  Hewlett-Packard Company makes no
40 * representations about the suitability of this software for any
41 * purpose.  It is provided "as is" without express or implied warranty.
42 *
43 *
44 * Copyright (c) 1996,1997
45 * Silicon Graphics Computer Systems, Inc.
46 *
47 * Permission to use, copy, modify, distribute and sell this software
48 * and its documentation for any purpose is hereby granted without fee,
49 * provided that the above copyright notice appear in all copies and
50 * that both that copyright notice and this permission notice appear
51 * in supporting documentation.  Silicon Graphics makes no
52 * representations about the suitability of this software for any
53 * purpose.  It is provided "as is" without express or implied warranty.
54 */
55
56/** @file stl_tempbuf.h
57 *  This is an internal header file, included by other library headers.
58 *  You should not attempt to use it directly.
59 */
60
61#ifndef _TEMPBUF_H
62#define _TEMPBUF_H 1
63
64#include <memory>
65
66namespace std
67{
68  /**
69   *  @if maint
70   *  This class is used in two places: stl_algo.h and ext/memory,
71   *  where it is wrapped as the temporary_buffer class.  See
72   *  temporary_buffer docs for more notes.
73   *  @endif
74   */
75  template<typename _ForwardIterator, typename _Tp>
76    class _Temporary_buffer
77    {
78      // concept requirements
79      __glibcxx_class_requires(_ForwardIterator, _ForwardIteratorConcept)
80
81	public:
82      typedef _Tp         value_type;
83      typedef value_type* pointer;
84      typedef pointer     iterator;
85      typedef ptrdiff_t   size_type;
86
87    protected:
88      size_type  _M_original_len;
89      size_type  _M_len;
90      pointer    _M_buffer;
91
92      void
93      _M_initialize_buffer(const _Tp&, __true_type) { }
94
95      void
96      _M_initialize_buffer(const _Tp& val, __false_type)
97      { std::uninitialized_fill_n(_M_buffer, _M_len, val); }
98
99    public:
100      /// As per Table mumble.
101      size_type
102      size() const
103      { return _M_len; }
104
105      /// Returns the size requested by the constructor; may be >size().
106      size_type
107      requested_size() const
108      { return _M_original_len; }
109
110      /// As per Table mumble.
111      iterator
112      begin()
113      { return _M_buffer; }
114
115      /// As per Table mumble.
116      iterator
117      end()
118      { return _M_buffer + _M_len; }
119
120      /**
121       * Constructs a temporary buffer of a size somewhere between
122       * zero and the size of the given range.
123       */
124      _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last);
125
126      ~_Temporary_buffer()
127      {
128	std::_Destroy(_M_buffer, _M_buffer + _M_len);
129	std::return_temporary_buffer(_M_buffer);
130      }
131
132    private:
133      // Disable copy constructor and assignment operator.
134      _Temporary_buffer(const _Temporary_buffer&);
135
136      void
137      operator=(const _Temporary_buffer&);
138    };
139
140
141  template<typename _ForwardIterator, typename _Tp>
142    _Temporary_buffer<_ForwardIterator, _Tp>::
143    _Temporary_buffer(_ForwardIterator __first, _ForwardIterator __last)
144    : _M_original_len(std::distance(__first, __last)),
145      _M_len(0), _M_buffer(0)
146    {
147      // Workaround for a __type_traits bug in the pre-7.3 compiler.
148      typedef typename std::__is_scalar<_Tp>::__type _Trivial;
149
150      try
151	{
152	  pair<pointer, size_type> __p(get_temporary_buffer<
153				       value_type>(_M_original_len));
154	  _M_buffer = __p.first;
155	  _M_len = __p.second;
156	  if (_M_len > 0)
157	    _M_initialize_buffer(*__first, _Trivial());
158	}
159      catch(...)
160	{
161	  std::return_temporary_buffer(_M_buffer);
162	  _M_buffer = 0;
163	  _M_len = 0;
164	  __throw_exception_again;
165	}
166    }
167} // namespace std
168
169#endif /* _TEMPBUF_H */
170
171